diff --git a/src/doc/book/lang-items.md b/src/doc/book/lang-items.md index 72a3c08225d03..de7dbab3f12ea 100644 --- a/src/doc/book/lang-items.md +++ b/src/doc/book/lang-items.md @@ -57,8 +57,8 @@ fn main(argc: isize, argv: *const *const u8) -> isize { 0 } -#[lang = "eh_personality"] extern fn eh_personality() {} -#[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} } +#[lang = "eh_personality"] extern fn rust_eh_personality() {} +#[lang = "panic_fmt"] extern fn rust_begin_panic() -> ! { loop {} } # #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {} # #[no_mangle] pub extern fn rust_eh_register_frames () {} # #[no_mangle] pub extern fn rust_eh_unregister_frames () {} @@ -73,8 +73,8 @@ Other features provided by lang items include: `==`, `<`, dereferencing (`*`) and `+` (etc.) operators are all marked with lang items; those specific four are `eq`, `ord`, `deref`, and `add` respectively. -- stack unwinding and general failure; the `eh_personality`, `fail` - and `fail_bounds_checks` lang items. +- stack unwinding and general failure; the `eh_personality`, + `eh_unwind_resume`, `fail` and `fail_bounds_checks` lang items. - the traits in `std::marker` used to indicate types of various kinds; lang items `send`, `sync` and `copy`. - the marker types and variance indicators found in diff --git a/src/doc/book/no-stdlib.md b/src/doc/book/no-stdlib.md index 6fd7cf66920d4..2604ca8d4cab7 100644 --- a/src/doc/book/no-stdlib.md +++ b/src/doc/book/no-stdlib.md @@ -55,7 +55,13 @@ fn start(_argc: isize, _argv: *const *const u8) -> isize { // provided by libstd. #[lang = "eh_personality"] #[no_mangle] -pub extern fn eh_personality() { +pub extern fn rust_eh_personality() { +} + +// This function may be needed based on the compilation target. +#[lang = "eh_unwind_resume"] +#[no_mangle] +pub extern fn rust_eh_unwind_resume() { } #[lang = "panic_fmt"] @@ -87,12 +93,18 @@ pub extern fn main(_argc: i32, _argv: *const *const u8) -> i32 { 0 } -// These functions and traits are used by the compiler, but not +// These functions are used by the compiler, but not // for a bare-bones hello world. These are normally // provided by libstd. #[lang = "eh_personality"] #[no_mangle] -pub extern fn eh_personality() { +pub extern fn rust_eh_personality() { +} + +// This function may be needed based on the compilation target. +#[lang = "eh_unwind_resume"] +#[no_mangle] +pub extern fn rust_eh_unwind_resume() { } #[lang = "panic_fmt"] @@ -104,7 +116,7 @@ pub extern fn rust_begin_panic(_msg: core::fmt::Arguments, } ``` -## More about the langauge items +## More about the language items The compiler currently makes a few assumptions about symbols which are available in the executable to call. Normally these functions are provided by @@ -112,15 +124,20 @@ the standard library, but without it you must define your own. These symbols are called "language items", and they each have an internal name, and then a signature that an implementation must conform to. -The first of these two functions, `eh_personality`, is used by the failure +The first of these functions, `rust_eh_personality`, is used by the failure mechanisms of the compiler. This is often mapped to GCC's personality function (see the [libstd implementation][unwind] for more information), but crates which do not trigger a panic can be assured that this function is never -called. Both the language item and the symbol name are `eh_personality`. - +called. The language item's name is `eh_personality`. + [unwind]: https://github.com/rust-lang/rust/blob/master/src/libpanic_unwind/gcc.rs -The second function, `panic_fmt`, is also used by the failure mechanisms of the +The second function, `rust_begin_panic`, is also used by the failure mechanisms of the compiler. When a panic happens, this controls the message that's displayed on the screen. While the language item's name is `panic_fmt`, the symbol name is `rust_begin_panic`. + +A third function, `rust_eh_unwind_resume`, is also needed if the `custom_unwind_resume` +flag is set in the options of the compilation target. It allows customizing the +process of resuming unwind at the end of the landing pads. The language item's name +is `eh_unwind_resume`. diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs index fabb3900ec648..4949e66de54c9 100644 --- a/src/libcore/lib.rs +++ b/src/libcore/lib.rs @@ -42,6 +42,11 @@ //! line. It is up to consumers of this core library to define this panic //! function; it is only required to never return. This requires a `lang` //! attribute named `panic_fmt`. +//! +//! * `rust_eh_personality` - is used by the failure mechanisms of the +//! compiler. This is often mapped to GCC's personality function, but crates +//! which do not trigger a panic can be assured that this function is never +//! called. The `lang` attribute is called `eh_personality`. // Since libcore defines many fundamental lang items, all tests live in a // separate crate, libcoretest, to avoid bizarre issues.